It's a good sign that there's not abnormal wear on them, that means she likely still has feeling in those paws, so it probably isn't DM. Maybe you can help her with her fear of turning that corner. Try putting her on a leash and walking her around the corner several times, and praise her when she does it normally. Something may have inadvertently spooked her about the spot, so now you have to work on her getting used to it again as a normal, safe spot! It's good you have a vet appointment scheduled, so they can check for any medical issues. The pacing at night will sometimes happen if an animal is uncomfortable, sure would be easier if they could talk and say "Mom, my tummy hurts" and the like.